Aircraft, military & specialist tyres

Aircraft tyre fitment is not a matter of preference. Which tyre may be fitted to a given aircraft is governed by the aircraft’s type certificate and the approved maintenance data that goes with it, and by the airworthiness approval held by the tyre itself. The part number in the approved documentation is the specification — the size alone is not enough, and a dimensionally identical tyre without the right approval is not an alternative.

Aircraft sizes use several conventions. The older inch designations, 6.00-6 and 5.00-5, give section width and rim diameter. Three-part designations such as 18×4.4 give overall diameter and section width, and metric designations such as 615×225 give overall diameter and section width in millimetres. Alongside the size, the ply rating, the rated inflation pressure and the speed rating are all part of the specification.

Fitting, inflation, inspection and any retreading are carried out under the approved maintenance data, by or under an appropriately approved organisation, and the inflation medium is specified there as well. We supply against a part number provided by the operator or the maintenance organisation. We do not advise on airworthiness, eligibility or approval status, and we will always refer that question back to the approval documents.

Aircraft towing, ground handling and hangar equipment sits alongside the aviation range without being subject to the same approval regime. These are industrial and commercial tyres selected for very high static loads at low speed, and often for puncture resistance above everything else.

The operating environment sets the priorities. Airside, tread that chunks or sheds becomes foreign object damage close to running engines, so casing integrity and inspection frequency matter more than tread life. Our port and airport range covers the mainstream ground support sizes held in stock.

Solid and foam-filled options are common here for the same reason they are common on a ramp: a puncture next to an aircraft is an operational event, not an inconvenience.

The 20 inch military radial sizes are the backbone of NATO-pattern wheeled logistics and support vehicles. They are built for a duty cycle no civilian truck tyre sees: full load on tarmac at speed, then the same load across soft ground at greatly reduced pressure, with the sidewall doing a large part of the work.

Specification is usually by vehicle and contract rather than by preference, and frequently references a stock number or a defence specification. Tell us the vehicle, the position and the reference, and we will source against it.

Sizes such as 1400×530-533 follow the metric convention of overall diameter, section width and rim diameter in millimetres. These are heavy, low-volume fitments with genuinely long lead times, and they should be planned rather than ordered against a breakdown.

Armoured vehicles are far heavier than the civilian platforms they are based on, so the load rating is the starting point and it is often two or three steps above the standard fitment for the same size. Under-specifying here shows up as heat failure, not as a soft ride.

Run-flat capability is provided by an insert inside the tyre — a composite or rubber ring on the rim that supports the tyre after a loss of pressure and allows the vehicle to travel a limited distance at a limited speed. The distance and speed are defined by the insert manufacturer and by the vehicle’s own specification, and must be observed. An insert is a mobility measure to get out of an incident, not a way to continue an operation.

Inserts change everything about fitting. They usually require a multi-piece or divided rim, specific tooling and trained fitters, and they add substantial unsprung weight. Confirm the wheel specification and the fitting capability at the same time as the tyre, not afterwards.

Specials are the fitments that fall outside every catalogue: obsolete sizes for machines still in service, non-standard rim diameters, unusually high ply ratings, and one-off requirements on plant that was built as a prototype or heavily modified.

Detailed information helps us assess specialist enquiries. A photograph of the sidewall, the rim marking, the machine plate and the load per wheel will usually get to an answer. A size read off a worn tyre on its own frequently will not, because the tyre that came off may itself have been the wrong one.

Where the original fitment is unavailable, we can review possible alternatives and explain their implications for rolling radius, load rating and rim compatibility. Any alternative must meet the machine’s approval and fitment requirements.

Road-rail vehicles, rail-mounted plant and infrastructure maintenance machines run on the highway and then on track, sometimes on the tyres themselves with guidance wheels deployed. That combination places unusual demands on the tyre and, more importantly, places it inside an approved vehicle configuration.

Where a vehicle is approved for on-track use, the tyre is part of what was approved. Changing size, construction or specification can invalidate that, so the infrastructure manager’s requirements and the vehicle’s approval documentation come first and the catalogue second.

Utility, tunnelling and infrastructure plant more generally tends to run high-ply industrial and earthmover fitments, often foam-filled because a deflation in a tunnel or on a possession is measured in lost hours rather than in tyre cost.

Mobile crane carriers and heavy haulage vehicles run very high axle loads at low speeds, with long periods stationary and outriggered. The governing figures are the load per wheel — which the manufacturer publishes and which is not simply the plated weight divided by the number of wheels — and the speed the vehicle is permitted to travel at.

Crane tyres also spend a lot of their life standing. Flat-spotting, casing set and ageing account for as many removals as wear, so date codes and sidewall condition are part of the inspection, not an afterthought.

Movement orders and abnormal load routes assume a vehicle configuration. Changing tyre size changes the ride height, the rolling radius and sometimes the axle weights, so check the paperwork before changing the fitment.

Foam filling replaces the air in a pneumatic tyre with a polyurethane fill, so it cannot deflate. On plant working in demolition, scrap, tunnelling or on any site where downtime is expensive, that removes the most common cause of a machine standing idle.

Consider the effect on the machine. A filled tyre is much heavier, it does not absorb shock the way an inflated tyre does, it runs hotter, and it cannot be repaired or retreaded afterwards. It also raises the load on axles, bearings and the machine structure. Above a certain speed and duty, filling is the wrong answer and a solid or a different tyre is the right one.

Our foam fill calculator gives the added weight for a given size, and the foam filling guide covers where it pays and where it does not.